3/3/2015
Objectives –
Identify the use, operations and applications of hydrographic surveying.
–
Familiarize with different sounding methods.
–
Solve point fixing problems.
–
Perform volume and discharge computations.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
1
3/3/2015
Outline –
–
Hydrography, Hydrographic Surveys, and Maps Operations in Hydro-Survey
–
Tides, Tidal Datums, and Tide Stations
–
Soundings
–
Point Fixing
–
Volume Computation
–
Discharge Measurement
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
2
3/3/2015
Outline –
–
Hydrography, Hydrographic Surveys, and Maps Operations in Hydro-Survey
–
Tides, Tidal Datums, and Tide Stations
–
Soundings
–
Point Fixing
–
Volume Computation
–
Discharge Measurement
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
2
3/3/2015
Hydrography Hydrography – the art and science of compiling and producing charts/maps, of water-covered areas of the Earth’s surface; includes charting of water column parameters, geology of the seabed sediments and positioning issues. study y of the Hydrology - the stud movement, distribution, and quality of water throughout the Earth. deals ls with with the Hydraulics - dea mechanical properties of liquids. Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Branch Overview Nautical Charting
Remote Sensing
Military Hydrography
Coastal Zone Management (dredging)
Offshore Construction
Offshore Seismic Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
Inland Waters Hydrography (dredging) GE 12 – General Surveying II
3
3/3/2015
Hydrographic Hydrogr aphic Surveys Process that determines depths and terrain configuration of the bottoms of water bodies, used to prepare hydrographic maps.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Hydrographic Surveying
Hydrographic surveys are those done on Hydrographic bodies of water such as a rivers, reservoirs, bay, harbor, lakes or oceans. Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
4
3/3/2015
Purposes 1. Determination of channel depths for navigation 2. Determination of quantities of bottom excavation 3. Location of rocks, sand bars, wrecks, coral reefs 4. Measurement of areas subject to silting Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Purposes 5. Offshore structure positioning 6. Construction of water supply, bridges, pipeline crossings, underground cable crossings and water storage 7. Flood control and management
5
3/3/2015
Some Project Types Related to Hydrography 1. Oil/Gas Development 2. Dredging 3. Sea Defences 4. Deep Sea Mining 5. Marinas 6. Outfalls
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Display of Hydrographic Data Boat Sheets – hydrographer’s worksheet used in the field to plot the details of the survey while it is still in progress. Smooth Sheets – office plots of all data gathered during survey. These represent the data after all corrections have been applied.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
6
3/3/2015
Display of Hydrographic Data
t r a h C c i h p a r g o r d y H
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Display of Hydrographic Data
p a M c i r t e m y h t a B
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
7
3/3/2015
Display of Hydrographic Data s l e d o M n o i t a v e l E l a t i g i D
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Operations in Hydro-Survey
Reconnaissance
Establishment of Horizontal Control
Establishment of Vertical Control
Topographic Survey
Hydrographic Survey
Hydrographic Chart/Maps or other products
Other products: a. Water volume in a body of water b. Amount of dredged material c. Discharge of a stream d. Fluctuation of level in a body of water Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
8
3/3/2015
International Hydrographic Organization (IHO) •
•
Sets hydrographic standards to be agreed upon by the member nations. As these standards are uniformly adopted, the products of the world's hydrographic and oceanographic offices become more uniform.
What do we do? Hydrographic Procedures: Determination of depths Determination of positions
The techniques used for these tasks depend on the water body’s size, required accuracy, equipment and personnel. Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
9
3/3/2015
Equipment for Hydrography Sounding Craft
Fathometer
Sounding Pole
Signals
Leadline
Tide Gauge
Sounding Machine
Sextant
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Equipment for Hydrography
launches,
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
10
3/3/2015
Equipment for Hydrography
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Equipment for Hydrography
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
11
3/3/2015
Equipment for Hydrography
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Equipment for Hydrography
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
12
3/3/2015
Sounding Party Chief of Party
Coxswain
Instrument Man
Lookout
Recorder
Signalman
Leadsman
Fathometer Attendant
Range lines – well-defined lines on courses whose position are known and along which soundings are taken. Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
13
3/3/2015
Tides
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Tidal Definitions Tide
High Water
Tidal Current
Low Water
Flood Tide
Tide Range
Ebb Tide
Tidal Day
Slack Water
Stand
Set and Drift
Tidal Waves
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
14
3/3/2015
Tides
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Types of Tides
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
15
3/3/2015
Neap and Spring Tides
Minimum Tide Range
Maximum
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
Tide Range
GE 12 – General Surveying II
Neap and Spring Tides
http://www.columbia.edu/itc/ldeo/v 1011x-1/jcm/Topic2/Topic2.html Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
16
3/3/2015
Co-tidal Charts
http://upload.wikimedia.org/wikipedia/commons/5/5e/M2_tidal_constituent.jpg Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Tidal Datums Specific tide levels used as surfaces of reference for depth measurements in the sea and as a base for the determination of elevation on land (localized). a.
Mean lower low water (MLLW)
b.
Mean low water (MLW)
c.
Mean sea level (MSL)
d.
Mean high water (MHW)
e.
Mean higher high water (MHHW)
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
17
3/3/2015
Tidal Datums
A tidal benchmark is a fixed vertical monument used to reference a local tidal datum.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Tide Stations To facilitate the process of establishing tidal datums, tide stations are operated at various locations.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
18
3/3/2015
“SOUNDING”
Soundings The process of measuring the depth of a body of water at a particular point.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
19
3/3/2015
How Depth is Measured A. Acoustic Techniques using Transducers 1. Singlebeam Echosounder 2. Multichannel Echosounder 3. Scanning Sonar/Profiler 4. Side Scan Sonar 5. Multibeam Echosounder
B. Other Non-acoustic Inspection Techniques 1. Lead Line 2. Sounding Pole 3. Wire and Bar Sweeps Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Acoustic Techniques using Transducers
20
3/3/2015
Transducers The antenna in the Sonar converts the electric energy from the transmitter to high frequency sound.
Sonar (SOund Navigation And Ranging) Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Acoustic Techniques using Transducers 1. Singlebeam Echosounder 2. Multichannel Echosounder 3. Scanning Sonar/Profiler 4. Side Scan Sonar 5. Multibeam Echosounder
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
21
3/3/2015
Singlebeam Echosounder
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Multichannel Echosounder
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
22
3/3/2015
Scanning Sonar/Profiler
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Side Scan Sonar
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
23
3/3/2015
Multibeam Echosounder
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Multibeam Echo Sounder Applications: 1. Dredging – for control on construction projects where a high resolution combined with a 100% coverage is needed.
2.
Offshore – used for inspection of pipelines, fall pipe projects, inspections of structures with ROVs.
3.
Pre-design surveys associated with pipeline and cable routes.
4.
Charting – used in areas where 100% coverage of the bottom is needed.; required by IHO for harbors, shipping channels and shallow areas with high traffic density.
5. Government – used in inspection of dams, dikes and harbors. If used for inspection works, the multi-beam is often used in surface looking mode. Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
24
3/3/2015
Non-acoustic Techniques
Lead Line
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
25
3/3/2015
Sounding Pole
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Wire and Bar Sweeps
Wire Drag Wire Sweep Sweep Bar
To be continued next meeting… Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
26
3/3/2015
FW group designations
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
“LOCATING SOUNDINGS/ POINT-FIXING”
27
3/3/2015
Locating Soundings The process of measuring the horizontal position of a depth of a body of water at a particular point.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Locating Soundings 1. Time Intervals Along a Range Line 2. Range Line and an Angle from Shore 3. Intersecting Range Lines 4. One Angle and Stadia Distance from Shore I ntersection Pr oblem 5. Two Angles from Shore Resecti on Pr oblem 6. Two Angles from Boat 7. Distances Along a Cross Rope or Wire 8. Direction and Vertical Angle 9. Electronic Positioning Systems 10. Land-Based Positioning Systems 11. GNSS Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
28
3/3/2015
Time Interval Along a Range Line Limited accuracy Known range line length Known, uniform speed of the boat Soundings are taken at regular intervals (echosounder) Locate positions of soundings by proportioning the time intervals • • • • •
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Range Line and an Angle from Shore base line
instrument
For short range lines (e.g. small lakes) Theodolite/transit at one end of the base line on shore is used to measure the angle from the base line to the LOS of the boat •
flags
θ s h o r e a r e a
•
e n i l e g n a r
e n i l e g n a r
e n i l e g n a r
e n i l e g n a r
e n i l e g n a r
marker buoys Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
29
3/3/2015
Intersecting Range Lines flags
base line s h o r e a r e a
b a s e l i n e
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
One Angle and Stadia Distance from Shore Theodolite/transit set up on shore, stadia rod on the boat Upper and lower stadia hair readings (HD) Read the azimuth from a reference line •
θ
instrument s h o r e a r e a
•
•
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
30
3/3/2015
Distances Along a Cross Rope or Wire (Tag-line Method) Stretching a graduated wire or cross rope along a narrow stream (for profiles) Employs a calibrated wire rope stretched perpendicular from hubs on a baseline to the survey boat •
•
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Direction and Vertical Angle Observe the depression angle from the instrument on a higher ground to the boat The horizontal distance is computed by using the trigonometric formula •
instrument HD α
DE
•
l a n d a r e a
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
W
A
T
E
R
GE 12 – General Surveying II
31
3/3/2015
Electronic Positioning Systems
Designed to measure the time of transit or difference in transit times of electromagnetic waves in the atmosphere Consists of: transmitter from the ship; 3 triangulation stations on the shore with known position; relay station on the shore with a transmitter, receiver and an amplifier; reference transmitter on the shore EPS tradenames for hydrographic surveys:
Shoran, Loran, Raydist, Del Norte
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Short-range Navigation (Shoran)
Method of short range electronic positioning for rapid determination of position even under adverse weather conditions Originally developed for blind bombing by the military and aerial reconnaissance Ship’s position is determined with respect to two previously established shore stations which transmit and receive signals simultaneously
80-120 km
Low frequencies Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
32
3/3/2015
Long-range Navigation (Loran)
The principle employed in long range navigation, similar to Shoran, except for the use and transmission of high pulses electromagnetic energy Follow curvature of the Earth better than low frequency signals Greater distances
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Electronic Position Indicator (EPI)
Method in hydrography which combines the principle of Shoran and Loran
Developed by USCGS
500-800 kms
Accuracy of Shoran
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
33
3/3/2015
Radio Acoustic Ranging (RAR)
The method of control used to determine the position of survey vessels Time of the subaqueous sound from the ship to reach 2 receiving stations of known position is used to determine the position Can be used during night time and even with low visibility
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Land-Based Positioning Systems
All these systems use time difference and trilateration techniques to determine a position.
Modulated light wave and infrared spectrum electronic distance measurement instruments can be used over relatively limited distances, usually less than 3 to 5 miles offshore.
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
34
3/3/2015
GNSS Global Navigation Satellite System (GNSS) is a real-time, all-weather, 24-hour, worldwide, 3-dimensional absolute satellite-based positioning system Two positioning services: - Precise Positioning Service - Standard Positioning Service Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Two Angles from Shore (Intersection Problem) An offshore vessel or platform can be triangulated by transit or theodolite angles observed from base line points on shore
instrument A
•
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
instrument B
α s h o r e a r e a
β
GE 12 – General Surveying II
35
3/3/2015
Two Angles from Shore
Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Intersection Problem Given the ff. data for an intersection problem, compute for the coordinates of A:
STA.
EASTING (m)
NORTHING (m)
B
3,369.287
2,890.836
C
3,300.259
3,082.183
STA OCC.
STA. OBS
HOR. ANGLE (clockwise)
B
A
0 ˚00’10”
C
81˚17’48”
B
0 ˚00’10”
A
64˚32’38”
C
C
B A Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
36
3/3/2015
C
Intersection Problem Steps in solving the intersection problem: 1. 2. 3. 4. 5. 6. 7.
B
A
Using the geometric property of triangles, the angles A, B and C should have a total of 1800. Solve for the unknown angle at A. Using the coordinates of the given points B and C, compute for the length of the baseline. Use sine law to determine the lengths of the other side/s. Compute for the azimuth of line BC given their coordinates. Given the interior angles, solve for the azimuths of the other line/s. Determine the coordinates of A using the length and azimuth of a line with one endpoint with known coordinates. Use the other side to compute for the coordinates of A as a check.
***Refer to FOOTE and DAVIS to find the direct (but long) formula for the intersection problem Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
Two Angles from Boat (Resection Problem) Involves simultaneous observation of two horizontal angles between three known objects from which the position of an offshore platform is resected
target A
•
D1
target B target C
s h o r e a r e a
θ
ϕ
boat with sextant Department of Geodetic Engineering Training Center for Applied Geodesy and Photogrammetry
GE 12 – General Surveying II
37
